1. Field of the Invention
The present invention relates to a communications switch system and, more particularly, to such a switch system that includes a call originator unit and a call receiver unit in order to implement a telephone line consolidation.
2. Description of the Prior Art
In the present local telephone switching devices, Touch (DTMF) Tones are used to provide call directions. Heretofore, there have been several drawbacks associated with the use of such tones. For example, the call originating device is typically unable to determine when the call receiving instrument has been connected and, therefore, cannot detect when to transmit call direction tones. Further, the call originating device typically cannot determine when the call receiving instrument has received the direction or selection tone.
Another drawback or disadvantage is that the call originating device must transmit the call direction tone within a very short time period. This time period starts when the receiving switch device is ready to detect the tone and ends just before the call is directed to a default device. The starting time of this period will vary. Specifically, the starting time of the time period is affected by the time it takes for a telephone call to traverse the originating caller's telephone central office, the long distance network, and the receiving caller's central office. Depending on the distance between the calling instrument and the call receiving instrument, one, two or all three of these delays may be interposed. The problem arises from the fact that the calling instrument, not knowing when the receiving switch device is ready to accept tones, must delay for the worst case connection time period, in addition to the detection time period. This long worst case delay will cause additional billable telephone time to the customer, and further, if it is too long, it may extend beyond the end of the detection time period causing the call receiving instrument to connect to the incorrect device. This would require another call attempt by the calling instrument also increasing telephone expense.
A further disadvantage is that if the calling instrument is automated, it typically has a limited ability to transmit the selection tones or to detect the results of the switch function. Accordingly, the incoming call can be lost.
A still further disadvantage is that the software for the calling instrument or device, such as a computer, may not have the capability of handling the number of characters that are needed to preprogram the long delays and the direction tones. Therefore, changes are required in existing software of the computer to insert sufficient pauses to ensure that any telephone line consolidation device has answered before the direction tone is sent. Also, the pauses will occur on the telephone line and, therefore, at the telephone caller's expense.
Accordingly, there has, heretofore, been a need for a communication system or device that interfaces with the calling instrument and an incoming telephone line having a receiving instrument and that uses the pulse or Touch (DTMF) Tones received from the calling instrument to direct the call to the receiving instrument. Further, such a communication device can be used without changes required in the originating device's software and without additional use of the telephone line. Still further, such a system needs to act within a very brief time period.
Furthermore, a need exists to cascade receiving switches to modularly increase the number of devices that can be addressed. This requires advanced abilities to transmit selection tones that include appropriate acknowledgment signals.